Abstract Well-planned initiatives aimed at accelerating patient recruitment is the key to all successful clinical research studies. Core B, the Recruitment and Sleep Study Core, will provide services to Project 01 and Project 02 in the areas of subject recruitment and performance and scoring of sleep studies. The proposed Core maintains the successful Recruitment and Sleep Study Core established with the previous program project grant. Core B is designed to provide the following important services: 1. Subject Recruitment: The Core will provide an infrastructure with well-trained staff who are proficient in all issues regarding protection of human subjects engaged in research, and who will take primary responsibility for recruitment of subjects in the projects. 2. Performance of Sleep Studies: The Core will standardize the performance and scoring of sleep studies at the University of Pennsylvania and the University of Iceland, and conduct sleep studies at the University of Pennsylvania for Project 1 and Project 2. 3. Performance of More Complex Sleep Studies: The Core will provide skilled technologists for more complex procedures such as performance of polysomnograms to determine critical airway pressure (Pcrit). 4. Review of Data: The Core will provide timely review (for quality and medical alerts) and scoring of all records and generate reports to be transferred to the Biostatical and Data Management Core (Core E). 5. Quality Assurance: The Core will conduct continuous quality assurance procedures to maintain high levels of technical performance of sleep testing at the University of Pennsylvania and University of Iceland as well as scoring of the sleep recordings at the Sleep Study Core Laboratory.